1. Field of the Invention
The present invention relates to an information reproducing method for reading information out from an information recording medium such as an optical card or an optical disk and an information recording method for writing information in the recording medium, and more particularly, to an information reproducing or recording method for an information reproducing or recording apparatus applied when track jump is unsuccessful in a seek operation on the information recording medium.
2. Related Background Art
The information recording media conventionally known include optical disks and optical cards for optically recording and reproducing information, fixed magnetic disks and floppy disks for magnetically recording and reproducing information, and magneto-optical disks, optical cards, etc. for optically and magnetically recording and reproducing information.
Generally, these information recording media have tracks consisting of a plurality of sectors. The tracks are provided with address information (hereinafter referred to as track numbers) indicating their positions in the information recording medium when the information recording medium is produced or formatted. Then, a desired track position is sought for, based on the track number, and recording or reproduction is carried out at that position. The information reproducing apparatus for reproducing the information in the recording medium is equipped with a memory for storing data of one or more tracks, and the cache technique is used upon reproduction of a desired sector in order to store data of all sectors including the desired sector in the track and decrease the number of track scans.
An example of operation of the conventional reproducing apparatus is next explained referring to the flowchart of FIG. 1. First, a host computer sends a logical address of an information reproducing portion together with a reproducing instruction to the reproducing apparatus. The reproducing apparatus having a memory for storing a part of data previously searched checks whether there is data of the logical address in the memory (step S11). If there is data, the reproducing apparatus transmits the data of the address in the memory to the host computer (step S15). If the data is absent, the apparatus obtains a physical address from the logical address, calculates a target track number corresponding to the physical address, and tries moving to the target track (step S12). Here, the apparatus scans the track to identify the track number, and checks whether the movement to the target track was unsuccessful (step S13). If unsuccessful, the apparatus again tries moving to the target track (step S12). If the movement to the target track was successful, data of the track is stored in the memory (step S14), and data of the desired sector is transferred to the host computer (step S15).
There is a limit to the capacity of the memory mounted in the reproducing apparatus. Thus, as to a method for abandoning stored data, a variety of proposals have been given; for example, first-in first-out abandonment, abandonment taking into account frequency of data reproduction address instruction, first-in last-out abandonment, etc.
An example of operation of a conventional recording apparatus is next explained referring to the flowchart of FIG. 2. First, receiving a recording instruction of data from the host computer (not shown), the recording apparatus (hereinafter referred to as a drive) moves a recording head to a target track corresponding thereto to look for a non-recorded area of an information recording unit (except for those registered as defective areas) (step S11). Since the track number cannot be identified without scanning the track, the recording head first scans the track to determine whether movement to the target track was successful (step S12). If the track is not the target track, the apparatus again looks for the target track (step S11). If it is the target track, recording and verification of data are carried out by scanning (steps S13, S14). Then, it is checked whether verification was successfully done (step S15). If there is an anomaly in verification, the apparatus performs altering processing, for example, preparation of movement to a next track (step S16). If the operation is normally ended, the recording processing is completed.
The above conventional example, however, had such a defect that the track scanning time for fault movement was wasted, because whether the movement to the desired track, instructed by the host computer, was unsuccessful was not able to be determined without scanning the track to which the head had moved.